Hello Shel, Friday, April 2, 2004, 6:19:28 PM, you wrote:
SB> I want to add more memory to one of my machines. How can I SB> determine what type of memory is needed? There seeems to be SB> many types. It should be in your motherboard's documentation, or if you don't have that, you can obtain the info from the manufacturer's site. You may also try AIDA32. It comes in 3 variants, the "Personal System Information" is free for personal use. I have used it for a while and I recommend it to anyone. You can get a lot of info about what's inside your computer, without opening the case. You can download it fom http://www.aida32.hu/aida32-download.php After you start the program expand the Motherboard section and select SPD. On the right you should see your currently installed memory's type and speed. It is a good idea to buy a new module that mathces these specs. But your motherboard may also support different speeds. So what's the catch? Suppose the following: Your motherboard supports SDRAM PC133 type memory. That is SDRAM at 133Mhz. You have now installed one SDRAM PC100 module. If you buy now a PC133, it will work, but *at 100MHz*. Your motherboard has a single memory bus, and it will run at the speed of the slowest memory module to ensure that all modules work. Sure all of the above must be considered in the context of the price of memory modules. If the difference in price between PC100 and PC133 is not all that much, you could just run the PC133 module at 100Mhz, and it will work fine. If the price is considerably higher, then it just don't worth the extra money (unless you change the slower modules to be also PC133). To further complicate the problem, let's consider the PC I want to build now: Motherboard: Gigabyte GA-7N400PRO2 with nForce2 Ultra 400 chipset. It supports 400Mhz DDRAM memory. CPU: AMD Athlon XP 2700 2.17GHz Barton. It has a 333Mhz FSB (Front Side Bus). Memory: Corsair DDRAM 400MHz (2 modules of 256Mb each). In a PC with a chipset that includes a Dual Independent Bus (DIB), the front side bus is the data path and physical interface between the processor and the main memory (RAM). So in this case, it runs at 333Mhz, and my 400Mhz DDRAM modules will run at 333Mhz. You may wonder why would I do this? I suppose I will be very fine with this system for a few years... then I will have to upgrade. Today's newer processors (the ones I can't afford now) have a 400Mhz FSB. So I will have to replace just the CPU in order to make an upgrade. If I would buy 333Mhz DDRAM now, I will have to replace that also. The price of a 333Mhz Corsair DDRAM module is 50.70USD, 400Mhz costs 55.10USD. So it definitely worth the extra 5$ in this case. How to determine your CPU's FSB using AIDA32: Select Motherboard/CPU. On the right look for "CPU Type". My PC in the office is "Intel Pentium IIIE, 800 MHz (6 x 133)". Here 133 is the FSB (6 is the CPU's multiplier to run at 800Mhz. I know that 6x133=798, but Intel says it is 800 <grin>). SB> Also, what about "speed?" Need the speed be SB> the same as what's currently installed? Not necessarily, but see above. Attila
